Releasing the former Stadia file transfer tools

The tools allow efficient and fast synchronization of large directory
trees from a Windows workstation to a Linux target machine.

cdc_rsync* support efficient copy of files by using content-defined
chunking (CDC) to identify chunks within files that can be reused.

asset_stream_manager + cdc_fuse_fs support efficient streaming of a
local directory to a remote virtual file system based on FUSE. It also
employs CDC to identify and reuse unchanged data chunks.

manifest/testdata/manifest_updater/executables/normal.txt

@@ -0,0 +1 @@
+*waves hand* This is not an executable!

manifest/testdata/manifest_updater/executables/script.sh

@@ -0,0 +1,17 @@
+#!/bin/sh
+# Copyright 2022 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+echo Hi!

manifest/testdata/manifest_updater/non_empty/a.txt

@@ -0,0 +1 @@
+aaaaaaaa

manifest/testdata/manifest_updater/non_empty/subdir/b.txt

@@ -0,0 +1 @@
+bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb

manifest/testdata/manifest_updater/non_empty/subdir/c.txt

@@ -0,0 +1 @@
+c

manifest/testdata/manifest_updater/non_empty/subdir/d.txt

@@ -0,0 +1 @@
+d